Clinical varieties of neuromuscular disease in debrancher deficiency
F. Cornelio, N. Bresolin, P. A. Singer, S. DiMauro and L. P. Rowland
Two men and one woman with debrancher deficiency had symptoms and signs of
neuromuscular disease. The two men had adult-onset and slowly progressive
weakness, distal muscle wasting, "mixed" electromyographic patterns, and
slow nerve conduction velocities; the initial diagnosis was
Charcot-Marie-Tooth disease in one patient and motor neuron disease in the
other. The woman had stunted growth, delayed motor milestones, and lifelong
nonprogressive weakness. A muscle biopsy specimen showed severe vacuolar
myopathy in all three cases. The glycogen concentration was increased
threefold to sixfold and had an abnormal iodine spectrum. Anaerobic
glycolysis in vitro showed impaired use of endogenous and exogenous
glycogen but normal use of hexose-phosphate glycolytic intermediates. These
three cases illustrated the clinical variety of neuromuscular disease in
debrancher deficiency. In patients with weakness of adult onset, the
diagnosis is impossible to make without performing a muscle biopsy.
